The invention relates to a feed pump with a driven impeller which rotates in a pump casing and in which a ring of guide vanes delimiting vane chambers is arranged in at least one of the end faces of said impeller, and with a part-annular channel which is arranged in the pump casing in the region of the guide vanes and which forms, with the vane chambers, a feed chamber for feeding a liquid from an inlet channel to an outlet channel.
Such feed pumps are known as peripheral or side channel pumps and are used, for example, in present-day motor vehicles for feeding fuel or washing fluid. When the impeller rotates, the guide vanes generate, in the feed chamber, a circulation flow running transversely to the direction of movement of the guide vanes. The guide vanes form, in the radially inner region of the impeller, the region of entry of the circulation flow into the vane chambers and, in the radially outer region, the exit region of said circulation flow. In order to adapt the feed pump to an intended characteristic curve and to the viscosity of the liquid to be fed, the angle of inclination of the guide vanes and the chamber volume can be calculated and adapted. This adaptation is critical for the efficiency of the feed pump in the intended instance of use.
A disadvantage of the known feed pump is that the dimensioning of the angle of inclination of the guide vanes may represent merely a compromise, because the conditions during the entry and exit of the circulation flow and therefore also the turbulence and frictional losses are different. These frictional losses and turbulences considerably reduce the efficiency of the feed pump.